The most commonly used method of resetting the transformer core of a forward converter is to allow the magnetizing inductance of the transformer to ring with a combination of lumped and parasitic capacitance during the off period of the power switch that controls current flow through the primary winding of the transformer. This method is inexpensive in application and allows for minimal size converter designs.
A drawback associated with self-driven synchronous rectifiers used in resonant reset forward converters is that it is difficult to maintain a suitable gate drive charge on the synchronous rectifier during the dead period of the converter. Conventional techniques for generating alternate gate drive signals to be provided to the synchronous rectifier often require the use of additional control circuitry. This additional control circuitry is often expensive and increases the overall size of the converter.